Update CHANGELOG for version 1.3.0

Added a warning about editor compatibility with browsers.

Author: thiagogq

CHANGELOG.md

@@ -5,7 +5,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## [1.3.0 - Unreleased]
+
+### Added
+
+- Warning informing users that the editor works best in Chromium‑based browsers.
 
 ## [1.2.3] - 2026-01-06